While a ThinkUp administrator may not want to keep application registration open to everyone, she might want to invite
a specific individual to register for an account. To do so, click on the “Create Invitation” button. ThinkUp will
provide a unique, single user registration link which expires in 7 days. Copy and paste that link into an email or
instant message to a user to invite that person to register for an account.

The invitation link is good for one-time use, and expires after 7 days.